MC,
The following was written very hurriedly and it's not very well organized, but I
hope you will find something of use in it.
Best,
Mike

Mike
Johnston
is the editor of Photo Techniques, a photographic
magazine published bimonthly in the USA . It is specifically targeted at more experienced
photographers and has extensive coverage on darkroom and darkroom techniques.

>>>>>>>>>>>>>>>

I tend to get in a lot of
trouble when I talk subjective lens-talk in public. I love lenses, and maybe half
of my photography is involved in simply trying lenses to see what they look like.

I'm no optical
expert in the scientific sense, so I'm often left "thinking" that I see
something and believing that "maybe" it may correlate to a scientific descriptive
term. I'd be much more at home in Japan, where subjective connoisseurship of lenses
is a well-established tradition. Here are a few of the things I believe about lenses:

# That the "cult"
of lens "sharpness" and quality evolved in parallel to the miniaturizing
of film formats. It's very difficult for most lenses to look bad contact printed,
or enlarged 3X; the smaller the film got, and the more it was enlarged, the more
the characteristics of the lens were exposed; so along with the interminable push
for more sensitive and finer-grained films and developers, the "cult of lens
quality" emerged.

Case in point:

Nobody ever looked at a Daguerreotype and said "not very sharp. Too bad the
lens was a dog." If you've seen a decent number of Daguerreotypes you'll know
what I mean.

# Nobody knows what anybody else means
by the term "sharpness." Resolution of ultra-fine detail? Contrast? At
what degree of resolution? Edge sharpness that accentuates boundaries? Some people
like one kind of "sharpness," others another.

# Sharpness doesn't matter. Seen from
a gestalt perspective, images can be very diffuse and broad-brush and still be recognizable,
in the same way extreme abstraction can still be "read": that is, a line
and two dots can be a "face," and vague fuzzy patterns of light and shade
can be figurative. Ever seen those "pictures" made from thousands of little
pictures? Fine detail in that case is little pictures that don't have anything to
do with Marilyn Monroe, or whatever the "big picture" is "of."
(Forgive all these quotation marks.) Fact is, fine detail resolution doesn't have
anything to do with why most pictures work as art--it almost never contributes to
greater recognition of the subject, or to meaning. I could provide a list as long
as your arm of great pictures in which even coarse detail can hardly be rendered.

Having said all this, why should a lens be "sharp" and what does that mean?

--Most lenses are loaded with aberrations of different kinds, most of which are visible
in pictures. BUT PEOPLE DON'T SEE THEM, I guess because they don't know what to look
for, or what they're looking at when they see it.

Case in point:

Many of our readers never noticed the quality of the out-of-focus blur until we did
our articles on "bokeh" (bo-ke, Japanese for "blur"). We know
because they wrote and told us. (Some people never wanted to notice it: we know because
they wrote and reamed us out, highly indignantly, for presuming to discuss it.) Yet
many, many photographs have large areas of out-of-focus blur and always have had
and always will have.

It's a technical
property of lenses. It's there in pictures. Why ignore it? Similarly, you can SEE
color fringing, linear distortion, coma, spherical aberration, falloff, and on and
on, in pictures. Some people don't "notice" flare ghosts or obvious falloff,
much less the many, much subtler cues as to how a lens is behaving.# Some lenses go "well"
or "not so well" with different kinds of films.
Many color photographers are very preoccupied with the optical property of color
transmission. This is not so much a concern with the film I use (Tri-X <g>).
That's a blatant example, but you can get as subtle as you want. Many descriptions
of a lens that begin, "This lens looks..." actually mean, "This lens
with this film looks...."

# You can't buy wine by the label,
books by the cover, etc. In the 1980s, German tycoon Heinrich Mandermann owned both
Rollei and Schneider, and Schneider built a set of wonderful new lenses for the Rollei
6000 series. Guess what? People wouldn't buy 'em. They wanted the magic word "Zeiss"
on the lenses, and they'd buy older, bigger, heavier, more expensive, worse-performing
lens designs to get it. Most of those Schneiders are now discontinued. German lenses
aren't "better" than Japanese lenses, Leica lenses aren't all better than
any other brand, etc.

# On the contrary, there do seem to
be "house tendencies" among optical companies. Zeiss lenses do tend to
have lousy out-of-focus blur; Nikon lenses do tend to be super-sharp-looking but
at the cost of a certain harshness that can make caucasian skin look pasty; Canon
does favor a smooth, high-res but not quite so high-contrast look that works best
with color film (because color can function as contrast: it can help distinguish
adjacent areas and their edges. Imagine two areas of equal value, but one red and
one green. In B&W, it may all be one undifferentiated gray; but in color, these
two areas would tend to, ah, stand out from each other. ZAP). Re Leica, some Japanese
savants, I'm told, can wax poetic regarding the philosophies of the era of Mandler
vs. the era of Kolsch.

Always. There is no exception
to this rule. Most of them don't even tell you how the disparate performance parameters
are weighted! For instance, what if money is no object to you, and image quality
is of paramount importance, and a lens tests weighs "value" highly in its
final rating? What it if rates distortion as unimportant, and you're an architectural
photographer who needs straight lines at the edge of the picture to look straight?
What if it penalizes a lens for severe falloff wide open, yet every time you shoot
wide open it is in "available darkness" with nothing but blackness and
no important subject content anywhere near the edges? What if it rates ultra-fine
detail resolution very highly but you use a grainy film with limited resolution?
What if it "tests" the lens by photographing a test target four feet away
at f/8, but you're an aerial photographer who needs to know how the lens does wide
open for subjects half a mile away?

# Well, there's a lot more to it than
this, of course. Where the fruit of all my investigations have led is that I sort
of understand what properties I personally tend to value in a lens for my own work
with my own film, and how a large number of the available lenses compare with each
other within the focal-length ranges I work with. I.e., I don't know much...and the
more I find out, the less I find I know. <g>

But here are my recommendations:

1. Believe the evidence. If you love
a lens but it's not "supposed" to be good, believe the pictures before
reputation, published test results, or the status of the brand.

2. Don't believe one or another property
should be important to you unless it is. If a lens is universally admired because
it is super-sharp, don't accept this uncritically as being a good thing. Maybe that
lens looks harsh to you; maybe your work needs a softer look.

3. New isn't necessarily
good. Manufacturers in many fields typically expend a lot of effort and engineering
expertise learning how to suck value OUT of a product--that is, to make it possible
to make a "good enough" or an "almost good enough" product that
can sell more cheaply and/or have a higher profit margin.

With one lens design
I've investigated thoroughly, I can virtually trace the bell curve as the makers
first learned how to improve it and pour value and performance IN, and then as they
subsequently discovered how and where they could cut corners and suck value back
OUT !

--i.e., how they could reduce
the number of elements, where they could get away with planar rather than spherical
surfaces, which surfaces could be single-coated or left uncoated as opposed to being
fully multicoated, how they could cheapen the barrel. The lenses at the top of the
bell curve perform best, and some of these were manufactured thirty years ago.

4. Good isn't necessarily that good.
Science can make much better lenses than any photographer will pay for, or than can
be purchased for use on any camera extant.

5. Bad isn't necessarily bad. There
are two parts to this rule. First, some very inexpensive lenses are surprisingly
good; and second, even many poor lenses are good enough....for some use or other.
Artists are people who can take tools and materials, perceive the properties of these
tools and materials, and apply them to good effect. Good photographers can make,
and have made, great photographs with really, really "bad"
lenses.

6. Never be blinded into thinking
that good tools = good work. The world is full of photographers who churn out sharp
but wretchedly poorly-seen pictures. They can break their own arms smugly patting
themselves on the back for owning the latest apo-this or aspherical-that, but regardless,
Johnston's eighth law still holds: crap is crap.

7. Despite the high popularity
of testing lenses and the great relish with which photographers argue the topic,
ever wondered why photographers have no enthusiasm for conducting simple surveys
with pictures?

Actually, much
of the seminal research into lens quality and exposure (in the 1930s and '40s) was
done in just this way. Pay attention to what viewers of your pictures notice and
tell you. Interestingly, the only lens I've ever used that got much in the way of
compliments from non-photographer viewers was a 40mm f/2 Rokkor-M.

8. Finally--this is again apposite to the foregoing
point--most viewers can't tell. Mushy feelings of delight at the optical prowess
of this or that lens squelching up from within ourselves is something we photographers
pursue for ourselves and for other photographers. Viewers of pictures just look at
the pictures, not how grainy the film is or how luminous the bloody shadow detail
is said to be or how many lp/mm the lens allegedly resolves on a test bench. How
would they know anyway? They have no standard of comparison. So, much of lens connoisseurship
is akin to masturbation: something one does for own's own diversion and gratification.
Best not to confuse it with something done for the sake of another, or, for that
matter, with anything important.

Lastly, 9.
Never sell
a good lens !The
three best lenses I've ever used are gone with the wind, swept out along with the
sundry detritus of this acquisitive hobby. Woe is me.